The present invention relates to a chain for a three-dimensional conveyor line used to three-dimensionally convey products such as beverages, foods, pharmaceuticals or the like.
As the conveyor chain of this type, there have been proposed for example the conveyor-belt chain link disclosed in the Japanese Published Utility Model Application No. 51389 of 1975 and the conveyor unit disclosed in the Japanese Patent No. 2622936.
Many of the above-mentioned conventional conveyor chains for use in the three-dimensional conveyor lines are disadvantageous in that they cannot provide any relatively wide conveying or supporting surface for the products which are to be conveyed because they are limited in lateral movement relative to each other. Also, of the chains having a relatively wide conveying surface, many have both the conveying-directional edges thereof projected back and forth from the shaft pin hinging the two adjacent chain links to each other. While a product is being conveyed obliquely or when the chain engages onto the sprocket, the projecting chain edges are likely to thrust up the product or make a large step between the conveying surfaces, so that the product will possibly be overturned or caught (or stalled).
The present invention has an object to overcome the above-mentioned drawbacks of the prior art by providing a chain for use in a three-dimensional conveyor line, adapted to convey products more smoothly.
(1) A chain for use in a three-dimensional conveyor line, according to the present invention comprises synthetic resin-made chain links endlessly connected together and of which two adjacent ones are hinged to each other by a shaft pin as set forth in claim 1, wherein:
each of the chain links includes a top plate part on which a product to be conveyed is placed, and a link part formed under the top plate part to hinge two adjacent chain links to each other;
the link part includes a head portion projecting frontward from the central front end of the top plate part and a pair of leg pieces projecting rearward from the right and left rear ends, separated from each other, of the top plate part;
the projecting head portion has the shaft pin penetrated through it and is formed circular at the upper surface thereof nearly along a circle whose center lies on the longitudinal axis of the shaft pin and smoothly contiguous to the upper surface of the top plate part;
the length of the top plate part in the conveying direction is set shorter than the chain pitch; and
the top plate part has a lower slant face formed on the front edge thereof while having formed in the middle of the rear edge thereof a curved concavity with a concave slant face.
(2) Also, the chain for use in a three-dimensional conveyor line, according to the present invention comprises synthetic resin-made chain links endlessly connected together and of which two adjacent ones are hinged to each other by a shaft pin as set forth in claim 2, wherein:
each of the chain links includes a top plate part on which a product to be conveyed is placed, and a link part formed under the top plate part to hinge two adjacent chain links to each other;
the link part includes a head portion having a circular wall projecting frontward from the central front end of the top plate part and a pair of leg pieces projecting rearward from the right and left rear ends, separated from each other, of the top plate part;
the projecting head portion has pivotally installed inside the circular wall of the projecting head part a bearing block through which the shaft pin is penetrated;
the circular wall of the projecting head portion has formed in the lateral sides thereof holes elongated in the conveying direction and in which the shaft pin are loosely fitted;
the projecting head portion is formed circular at the upper surface thereof nearly along a circle whose center lies on the longitudinal axis of the shaft pin and smoothly contiguous to the upper surface of the top plate part;
the length of the top plate part in the conveying direction is set shorter than the chain pitch; and
the top plate part has a lower slant face formed on the front edge thereof while having formed in the middle of the rear edge thereof a curved concavity with a concave slant face which matches the upper surface of the projecting head portion of the adjacent chain link.
(3) Also, the chain for use in a three-dimensional conveyor line, according to the present invention comprises synthetic resin-made chain links endlessly connected together and of which two adjacent ones are hinged to each other by a shaft pin as set forth in claim 3, wherein:
each of the chain links includes a top plate part on which a product to be conveyed is placed, and a link part formed under the top plate part to hinge two adjacent chain links to each other;
the link part includes a head portion projecting frontward from the central front end of the top plate part and a pair of leg pieces projecting rearward from the right and left rear ends, separated from each other, of the top plate part;
the projecting head portion has a shaft pin penetrated through it and is formed circular at the upper surface thereof nearly along a circle whose center lies on the longitudinal axis of the shaft pin and smoothly contiguous to the upper surface of the top plate part;
the top plate part has recesses formed in the front end portion thereof and projections formed at the rear end portion thereof correspondingly to the recesses to be received in the recesses when the chain links sway laterally; and
the top plate part has a lower slant face formed on the middle rear edge thereof a curved concavity with a concave slant face which matches the upper surface of the projecting head portion of the adjacent chain link.
In any of the chains for three-dimensional conveyor line described in (1) to (3), the distance from the longitudinal axis of the shaft pin to the upper surface of the top plate part should desirably be set short and the step between the top plate part and top of the pair of leg pieces be set relatively large.